This disclosure relates to a gas turbine engine, and more particularly to gaspath leakage seals for gas turbine engines.
Gas turbine engines, such as those used to power modern commercial and military aircrafts, generally include a compressor section to pressurize an airflow, a combustor section for burning hydrocarbon fuel in the presence of the pressurized air, and a turbine section to extract energy from the resultant combustion gases. The airflow flows along a gaspath through the gas turbine engine.
The gas turbine engine includes a plurality of rotors arranged along an axis of rotation of the gas turbine engine. The rotors are positioned in a case, with the rotors and case having designed clearances between the case and tips of rotor blades of the rotors. It is desired to maintain the clearances within a selected range during operation of the gas turbine engine as deviation from the selected range can have a negative effect on gas turbine engine performance. The case typically includes an outer airseal located in the case opposite the rotor blade tip to aid in maintaining the clearances within the selected range. The outer airseals are mounted in the case, but often result in high heat transfer from the gaspath up into the flanges of the case. This results in faster case response than is often desirable, resulting in clearances outside of the selected range. Mass is often added to the case to slow the case response, but has limited effectiveness, and also increases the weight of the gas turbine engine.